1. Field of the Invention
This invention relates to ink recording devices and more particularly to a combination shield and wiper for the writing head of such devices.
2. Prior Art
Some recording devices, such as high speed printers and the like, include ink jet devices which have a moving writing head which dispenses bursts of ink from a number of orifices in the writing head, the ink being directed at a record carrier medium such as paper which is in opposition to an end face of the writing head.
In such ink recording devices the writing head may be moved lengthwise along a writing head carrier with the movement controlled by a drive device. The writing head can, in some presently used embodiments, consist of a mosaic head in which a plurality of piezoelectrically driven writing jets are positioned in a mosaic pattern.
The writing jets of such devices may be supplied with writing fluid or ink from an ink supply and the individual jets activation is controlled by a character generator. The jets of the writing head are formed by somewhat cylindrical bores which are surrounded by piezoelectric drive elements. The operating open ends of the bores are located at an end face of the writing head and a nozzle plate may be provided on the end face, the nozzle plate having a number of openings therethrough defining the bore exits.
In normal practice, writing heads of the above-described type are positioned in close spaced relationship to the record carrier, which may for example be a roll of paper. Due to this close positioning, often times dirt will be lodged against the nozzle plate with attendant adverse operating results. Such dirt contamination of the nozzle plate is frequently encountered during paper change or change of such other record carriers as may be used in the particular construction. Examples of other record carriers used are films, fabrics and the like.
Additionally, during changing of the record carrier, since it must be paired in close proximity to the writing head, and since the writing head is normally filed with ink, it is possible for the record carrier itself to become soiled by the ink.
It would therefore be an advance in the art if such ink writing devices as above described could be provided with mechanism which protects both the record carrier and the writing head from soiling during those times when the writing head is not being used and when the carrier is being changed. It would also be an advance in the art to provide method and apparatus for cleaning, automatically, the nozzle plate or other end face of the writing head.